package chpt08;

import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class SalesStatistics {
	public static void main(String[] args) throws IOException{
		try(Scanner in = new Scanner(new File("sales.dat"))){
			int n;
			double sum=0.0;
			n = in.nextInt();
			for(int i=0;i<n;i++) {
				sum += in.nextDouble();
			}
			System.out.println("average:"+sum/n);
		}
	}
}
